The invention relates to tape drive storage devices, and in particular, to an ejection assembly for tape drives that prevents over ejection of a tape cartridge from the tape drive.
Digital data is stored on tape drives utilizing a variety of designs, but in all cases, magnetic tape media is wound between a pair of tape reels as data is transferred to or from the tape media. In the art of data storage, the physical space required to store data is an important concern. To conserve space, tape drives often use a single reel tape cartridge design, which utilizes a supply reel located within a removable tape cartridge and a takeup reel located within the tape drive.
One popular application for single reel tape drives is in automated tape library systems. An automated tape library system contains a plurality of tape drives and a plurality of tape cartridge storage locations. An automatic retrieval/transport mechanism services the plurality of tape drives to transport tape cartridges between the plurality of tape drives and the storage locations. For example, the automatic retrieval/transport mechanism is pre-programmed to retrieve tape cartridges from their assigned tape cartridge storage locations in the automated cartridge library system and load the retrieved tape cartridges into the tape drives for data storage. When a tape drive is finished with a tape cartridge, the tape cartridge is ejected from the tape drive. The automatic retrieval/transport mechanism retrieves the tape cartridge from the tape drive and returns it to its assigned tape cartridge storage location.
To enable retrieval of the tape cartridge from the tape drive by the automatic retrieval/transport mechanism, the ejection of the tape cartridge must be accurately regulated to consistently eject the tape cartridge to a precise retrieval position. Referring to FIGS. 1 and 2, a spring loaded cartridge ejection assembly 100 accurately regulates ejection of the tape cartridge 102. During insertion of the tape cartridge 102 into the tape drive 106, the tape cartridge 102 engages an ejection carriage 103. The ejection carriage 103 slides in frame 105 along insertion direction A until it locks into a loaded position. As the tape cartridge 102 engages the ejection carriage 103, a carriage pin 101 inserts into an aperture 108 in the tape cartridge 102, engages a supply reel lock 200, and rotates the supply reel lock 200 to unlock the supply reel 107 as illustrated by FIG. 2. During ejection of the tape cartridge 102, the ejection carriage 103 is released from the loaded position and driven by spring 104 in direction B to slide the tape cartridge 102 out of the tape drive 106 to an ejected position. A rotary damper 109 controls the ejection speed and limits the momentum of the tape cartridge 102 during movement of the tape cartridge 102 from the loaded position to the ejected position.
After the tape cartridge 102 is in the ejected position, the carriage pin 101 and supply reel lock 200 are designed to remain engaged as illustrated by FIG. 2, until the tape cartridge 102 is pulled from the tape drive 106 by hand or by the automatic retrieval/transport mechanism. Unfortunately, the force required to disengage the 15 carriage pin 101 and supply reel lock 200 is only about 40 to 50 grams, thus several conditions exist that cause premature disengagement or an over ejection error as it is known in the art. During an over ejection error, the tape cartridge 102 moves beyond the unloaded position of the ejection carriage 103. The over ejected tape cartridge 102 often cannot be removed by the automatic retrieval/transport mechanism, requiring human intervention to reposition the tape cartridge 102 for retrieval by the automatic retrieval/transport mechanism. One condition that causes an over ejection error in tape drives is the inherent vibration of the tape cartridge library system. These vibrations cause the tape cartridge 102 to vibrate beyond the unloaded position of ejection carriage 103 out of the tape drive 106. Another condition that causes an over ejection error is variations in the tolerances of the ejection spring 104 over the life of the tape drive 106. Yet another condition that causes an over ejection error is variations in the performance of the rotary damper. Finally, another condition that causes an over ejection error is variations in friction between the tape cartridge 102 and the tape drive 106 that cause the ejection carriage 103 to over eject the tape cartridge 102.
The present invention overcomes the problems outlined above and advances the art by providing an ejection assembly that prevents over ejection errors in tape drives. The ejection assembly comprises an ejection carriage mounted in a tape drive that includes a carriage pin integrally formed in one end of the ejection carriage, a frame, a rotary damper and a spring. The ejection carriage slides within the frame during insertion and ejection of the tape cartridge in the tape drive. The spring connects between the frame and ejection carriage and provides the force to eject the tape cartridge from the tape drive. The rotary damper controls the momentum of the ejection carriage within the frame during ejection of the tape cartridge. The present ejection assembly improves over the prior art by including a rib that is integrally formed on the carriage pin. The rib is configured to form a snap connection with the supply reel lock of a tape cartridge as the tape cartridge is inserted into the tape drive. The snap connection between the rib and the supply reel lock secures the tape cartridge to the ejection carriage during insertion and ejection of the tape cartridge in the tape drive. The snap connection is not released until a significant external force is applied on the tape cartridge after the tape cartridge is ejected from the tape drive. In the context of the present invention ejecting the tape cartridge from the tape drive is defined as the process of moving the tape cartridge out of the tape drive to an ejected position. The ejected position is representative of a position where a user or an automatic retrieval/transport mechanism may remove the tape cartridge from the tape drive.
A first advantage of the present ejection assembly is that the rib on the carriage pin can be configured to different dimensions to control the amount of external force required to remove the tape cartridge from the tape drive. A second advantage of the present ejection assembly is that it provides a low cost solution to the over ejection error problem. A third advantage of the present ejection assembly is that it does not require an altered tape cartridge format. Similarly, a fourth advantage of the present ejection assembly is that it does not require modification of conventional retrieval/transport mechanisms in automated tape library systems. It can be appreciated that not modifying the tape cartridge format or the retrieval/transport mechanism represents a significant advantage to consumers whose data is currently stored on conventional tape cartridges in conventional tape cartridge library systems.